Tiffen 4x5.650 Hot Mirror Infrared Neutral Density Filters 0.3-2.1 reduce the amount of light passing through the camera lens without changing the color of the scene, while also reducing the amount of infrared light entering the camera. Especially useful in bright light conditions to help prevent over exposure. Allows proper exposure at wider lens openings, for reduced depth-of-field, and to highlight a key subject by making foreground and/or background out of focus. Permits slower shutter speeds for blurred motion effects in still photography.

The introduction of the hot mirror enables powerful filtration that is unparalleled to conventional IRND filters.

An ND 0.3 (also known as ND3) allows you to open the camera aperture one full stop OR, on motion picture cameras you can reduce the frame rate by 50% (24fps to 12fps). For still photography you can reduce the shutter speed by 50% (1/250th to 1/125th)

An ND 0.6 (aka ND6) allows you to open the camera aperture two full stops OR, on motion picture cameras you can reduce the frame rate by cutting it in half twice (24fps to 12 fps to 6fps). For still photography you can reduce the shutter speed by half twice (1/250th to 1/125th to 1/64th)

An ND 0.9(aka ND9) allows you to open the camera aperture three full stops OR, on motion picture cameras you can reduce the frame rate by cutting it in half three times:(24fps to 12 fps to 6fps to 3fps). For still photography you can reduce the shutter speed by half three times: (1/250th to 1/125th to 1/64th to 1/30th)

An ND 1.2(aka ND12) allows you to open the camera aperture four full stops OR, on motion picture cameras you can reduce the frame rate by cutting it in half four times:(24fps to 12 fps to 6fps to 3fps to 1.5fps). For still photography you can reduce the shutter speed by half four times: (1/250th to 1/125th to 1/64th to 1/30th to 1/15th)

An ND 1.5(aka ND15) allows you to open the camera aperture five full stops OR, on motion picture cameras you can reduce the frame rate by cutting it in half five times. For still photography you can reduce the shutter speed by half five times.

An ND 1.8(aka ND18) allows you to open the camera aperture six full stops OR, on motion picture cameras you can reduce the frame rate by cutting it in half six times. For still photography you can reduce the shutter speed by half six times.

An ND 2.1(aka ND21) allows you to open the camera aperture seven full stops OR, on motion picture cameras you can reduce the frame rate by cutting it in half seven times. For still photography you can reduce the shutter speed by half seven times.